Buggy code:
public abstract class SelectionScriptLinker extends AbstractLinker { public static final String USE_SOURCE_MAPS_PROPERTY = "compiler.useSourceMaps" ; protected static final String COMPUTE_SCRIPT_BASE_JS = "com//google//gwt//core//ext//linker//impl//computeScriptBaseOld.js" ; protected static final String FRAGMENT_EXTENSION = ".cache.js" ; protected static final String FRAGMENT_SUBDIR = "deferredjs" ; protected static PermutationsUtil permutationsUtil = new PermutationsUtil ( ) ; protected static final String PROCESS_METAS_JS = "com//google//gwt//core//ext//linker//impl//processMetasOld.js" ; private static final String CHUNK_SIZE_PROPERTY = "iframe.linker.script.chunk.size" ; private static final String PROP_FRAGMENT_SUBDIR_OVERRIDE = "iframe.linker.deferredjs.subdir" ; public static String splitPrimaryJavaScript ( StatementRanges ranges , String js , int charsPerChunk , String scriptChunkSeparator , LinkerContext context ) { } protected static void replaceAll ( StringBuffer buf , String search , String replace ) { } private static char lastChar ( StringBuilder sb ) { } @ Override public ArtifactSet link ( TreeLogger logger , LinkerContext context , ArtifactSet artifacts ) throws UnableToCompleteException { } @ Override public ArtifactSet link ( TreeLogger logger , LinkerContext context , ArtifactSet artifacts , boolean onePermutation ) throws UnableToCompleteException { } @ Override public boolean supportsDevModeInJunit ( LinkerContext context ) { <START_BUG> return ( getHostedFilename ( ) ) != "" ; <END_BUG> } protected int charsPerChunk ( LinkerContext context , TreeLogger logger ) { } protected Collection < Artifact < ? > > doEmitCompilation ( TreeLogger logger , LinkerContext context , CompilationResult result , ArtifactSet artifacts ) throws UnableToCompleteException { } protected List < Artifact < ? > > emitSelectionInformation ( String strongName , CompilationResult result ) { } protected EmittedArtifact emitSelectionScript ( TreeLogger logger , LinkerContext context , ArtifactSet artifacts ) throws UnableToCompleteException { } protected String fillSelectionScriptTemplate ( StringBuffer selectionScript , TreeLogger logger , LinkerContext context , ArtifactSet artifacts , CompilationResult result ) throws UnableToCompleteException { } protected String generateDeferredFragment ( TreeLogger logger , LinkerContext context , int fragment , String js , ArtifactSet artifacts , CompilationResult result ) throws UnableToCompleteException { } protected byte [ ] generatePrimaryFragment ( TreeLogger logger , LinkerContext context , CompilationResult result , String [ ] js , ArtifactSet artifacts ) throws UnableToCompleteException { } protected String generatePrimaryFragmentString ( TreeLogger logger , LinkerContext context , CompilationResult result , String js , int length , ArtifactSet artifacts ) throws UnableToCompleteException { } protected String generateSelectionScript ( TreeLogger logger , LinkerContext context , ArtifactSet artifacts ) throws UnableToCompleteException { } protected String generateSelectionScript ( TreeLogger logger , LinkerContext context , ArtifactSet artifacts , CompilationResult result ) throws UnableToCompleteException { } protected abstract String getCompilationExtension ( TreeLogger logger , LinkerContext context ) throws UnableToCompleteException { } protected String getDeferredFragmentPrefix ( TreeLogger logger , LinkerContext context , int fragment ) { } protected String getDeferredFragmentSuffix2 ( TreeLogger logger , LinkerContext context , int fragment , String strongName ) { } protected final String getFragmentSubdir ( TreeLogger logger , LinkerContext context ) throws UnableToCompleteException { } protected String getHostedFilename ( ) { } protected abstract String getModulePrefix ( TreeLogger logger , LinkerContext context , String strongName ) throws UnableToCompleteException { } protected String getModulePrefix ( TreeLogger logger , LinkerContext context , String strongName , int numFragments ) throws UnableToCompleteException { } protected String getModuleSuffix2 ( TreeLogger logger , LinkerContext context , String strongName ) throws UnableToCompleteException { } protected String getScriptChunkSeparator ( TreeLogger logger , LinkerContext context ) { } protected abstract String getSelectionScriptTemplate ( TreeLogger logger , LinkerContext context ) throws UnableToCompleteException { } protected void maybeAddHostedModeFile ( TreeLogger logger , LinkerContext context , ArtifactSet artifacts , CompilationResult result ) throws UnableToCompleteException { } protected void maybeOutputPropertyMap ( TreeLogger logger , LinkerContext context , ArtifactSet toReturn ) { } protected StringBuffer readFileToStringBuffer ( String filename , TreeLogger logger ) throws UnableToCompleteException { } protected String wrapDeferredFragment ( TreeLogger logger , LinkerContext context , int fragment , String script , ArtifactSet artifacts ) throws UnableToCompleteException { } protected String wrapPrimaryFragment ( TreeLogger logger , LinkerContext context , String script , ArtifactSet artifacts , CompilationResult result ) throws UnableToCompleteException { } }

Fix:
return ! ( "" . equals ( getHostedFilename ( ) ) ) ;